The present invention relates to the field of retractable devices for ejecting and retracting flexible members and in particular to a system, apparatus, and method for regulating the engaging forces of retracting systems.
Retractable systems are often used to dispense, receive, and store flexible members. The flexible member which may be a wire, cable, rope, cord, hose, tube, chain, or tape measure, for example, is typically drawn from a storage enclosure to a length that is acceptable for use. When the flexible member is no longer needed, the member can be retracted and stored in the enclosure.
A variety of conventional storage retraction devices spirally wind and eject flexible members by employing spring driven spindles. Clockwise rotation of the spindle simultaneously ejects the flexible member from the enclosure while storing a retractile force in the spring driven system. When the flexible member is extended to an appropriate length, a tension control assembly is engaged allowing the flexible member to be used for its intended purpose. When the flexible member is ready to be stored, a modest draw on the flexible member usually releases the tension control assembly allowing the flexible member to recoil into the enclosure around the spindle.
The use of a spring drive in some retractable devices sometimes causes a random and disorderly recoil of the flexible member. As greater lengths of the flexible member are withdrawn from an enclosure, the spring driven system stores retraction energy proportional to the length of the flexible member ejected. The initial retraction of the flexible member subjects many storage retraction devices to a high rotational force. The transition from storing retraction forces to withdrawing the flexible member subjects these devices to a substantial transitional force that causes damage to some devices. The unregulated retraction of flexible members frequently occurs at an increasing velocity preventing a neat and orderly retraction. If the flexible member does not become tangled or damaged as it is recoiled, the increasing rotational velocity of the spindle may recoil the entire flexible member into the enclosure. When the flexible member is completely received by the enclosure, the flexible member may not be accessible and may damage the retracting device.
Some conventional retractable devices use fluid damper assemblies to limit the retraction velocity of the spindle. In these devices, a volume of liquid is subject to significant shear forces that result from the retraction of a substantial length of the flexible member. If the liquid seal is compromised, the retracting forces in such devices may not effectively damp the rotational velocity of the spindle subjecting the spindle and the flexible member to the unregulated recoil energy released by the spring driven system.
In light of the strengths and weaknesses of the conventional art, there is a need for a retractable system, apparatus, and method that regulates the engaging forces of retracting devices without relying on a fluid damper assembly. The system, apparatus, and method should be capable of providing a damping force proportional to the recoil velocity of the spindle, providing damping forces even if the damping assembly is compromised, and function in a compact modular assembly that is easy to manufacture, assemble, and store.